To echo what was said earlier, this is exactly what we wanna see in MLS. Either with academy signings or even signing young foreign players, have them for a few years and develop them and eventually move them on.
The fact that Murillo seemed to be a locker room cancer this past season makes this an easy move to swallow.
Add right back as a position of need for a starter level player to come in. Still not convinved by Duncan.